Anchor lug for pipe tension wire



May 19, 1959 w. R. KELL 2,887,130

ANCHOR LUG FOR PIPE TENSION WIRE Filed Oct. l0, 1957 United StatesPatent O 2,887,130 ANcHoR LUG Fon PIPE TENSION WIRE Waldo R. Kell, LosAngeles, Calif., assignor to `Cen-Vi-Ro Pipe Corporation, South Gate,Calif., a corporation of Delaware Application october 1o, 1951, serialNo. 689,323

9 claims. (el. 13s-s4) The inventionrelates to molded concrete pipes and`has `particular reference to those pipes currentlyidentified as `degreeto demonstrate the technique as practical and successful, havehadcertain shortcomings. It will be appreciated that in applying heavywire of a gage suicient to apply acceptable tension to pipes or moldedconcrete cores, two, three, four and more feet in diameter, a wire ofvery ample diameter is needed. Also in view of such circumstances theaggregate tension to accomplish the intended purpose is many thousandsof pounds and whatever anchoring lug or anchoring means is made use ofmust be one capable of being applied `in the first place while the wireis held under tension and mustnaturally be sumciently rugged in its gripon the wire and its grip t within the molded concrete mass to hold thattension with an acceptable degree of insurance under all thecircumstances which may be encountered. n

In the first instance the anchor lug must be one capable `of beingsecurely anchored in the molded concrete when the concrete is poured andpermitted to set. vCertain limitations are inherent in the problem,`one. of them being the very denite maximum thickness of the core wallwhich requires that the concrete anchoring elements be shallow enough tobe completely contained within the wall thickness leaving an adequateamount of protecting concrete on both sides. p

Another factor lies in the fact that the anchoring device must not be ofsuch character as to protrude unnecessarily inasmuch as after theanchoring of zthe wire4 takes place, a protective outer coating ofconcrete `or other acceptable `plastic material must be applied to a'depth capable of completely covering the `anchoring means. Also becauseof the wire being under very heavy tension, it is most needful to havethe anchoring means one which can be quickly and easily engaged when thetension is at its greatest.

It is accordingly among the objects of the invention to provide a newandimproved anchoring means for the ends of Wire under tension whenapplied to concrete cores for prestressing purposes which is rugged indesign and of such shape and proportions that it can be easily embeddedin the core while at the same time providing facility for readilyengaging the prestressing wire.

Another object of the invention is to provide a new and improvedanchoring lug device which is preferably ush with the exterior surfaceof the core, `thereby making it possible to present a relativelyunobstructed outer surface on the core for the subsequent application ofa protective exterior coating.` p

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Another object of the invention is to provide a new and improvedanchoring lug means for prestressing wire which is positive in itsapplication to the wire so that no slippage will occur during the makingof the connection and which also is of such proportions that it can beembedded properly within the concrete core to a sufhcient depth from theopposite surfaces thereof.

Still another object of the invention is to provide a new and improvedanchoring lug means for prestressing `wire which is of such characterand proportions that it can be made to fit wire of varying diameterswithout need forchange inthe anchoring device itself.

Still another object of the invention is to provide a new and improvedanchoring lug means which is of relatively simple construction and whichis complete in itself when embedded in the core during the moldingprocess such that it is immediately ready for the reception of the endof the wire to which an appropriate anchoring sleeve has been attachedin a fashion and at a location such that the sleeve and Wire can bequickly and effectively slipped into engagement with the `embedded lugcomponents and thereby make an immediate permanent connection. p

Still further among the objects of the invention is to provide a new andimproved anchoring lug means which is extremely simple and inexpensiveinits construction and assembly and which is also of such character thata dependable anchoring attachment can be made very rapidly in such formthat its effectiveness is assured.

With `these and other objects in view, the invention con- `sists in theconstruction, arrangement and combination of the various parts` of thedevice whereby the objects contemplated are attained, as `hereinafterset forth, pointed out in the appended claims and illustrated in theaccompanying drawings. i

In the drawings:

Figure 1 is a fragmentary cross-sectional` view of a molded concretecore to which the prestressing wire has been` applied and connected tothe lug means and wherein the protective coating is also shown.

Figure 2 is a plan view of the anchoring device connected to aprestressing wire prior to the application of the coating.

Figure 3 is a transverse sectional` vie-w taken on the line 3--3 ofFigure 2.

Figure 4 is a transverse sectional view showing the locating of aportion of the anchor lug device in a fo for the pouring of the core. p

In an embodiment of the invention chosen for the purpose of illustrationthere is shown a molded concrete core 10 to which a prestressing wire 11has been applied and ultimatelycovered with a'plastic coating 12. Inthis instance the coating is a concrete grout. p

More particularly, the core 10 illustrated and described is oneconstituting molded concrete throughout which when properlyforrnedwithin a metal form 13 may be constructed without eitherlongitudinal or circumferential reinforcement if desired. The core hasan inner surface 14 and an outer surface 15. As a matter of interest itmay be noted that in making cores of this general description acylindrical form like the form 13 is customarily placed in a frame andthere rotated and preferably vibrated while moist concrete is deposited.During this time, the concrete takes a level which determines thethickness of the wall of the core. The outer surface of the cere isdetermined by an interior surface 16 of the form 13. The inner surface14 is determined by oneor another of the usual methods of rolling orscreening. x

The anchor lug comprises `a body herein having the form of a somewhatrectangular block indicated generally by the reference character 17. Inthe chosen form the lug comprehends a plate serving as a bottom 18, sidewalls 19 and 20 and end walls `21 and 22 which form Patented May 19,1959 3 a box. It is significant that the end wall. 22. is materiallythicker than the end wall 21. It is also noteworthy that the upper edgesof the sidewalls 19 and 20 throughout their length, as well as thebreadth of the end walls is in an arcuate form conforming to thecurvature of the outer surface 15 of the core 10.

In the end wall 22 there is formed an open end slot 25 which extendsinto the end wall to a depth almost, but not quite equal to, the insideheightl of the wall. It is further important that an insideV face 28 isoblique or undercut in a direction such that the outer edge of the wallis thicker than the wall at the bottom. As shown, the side walls and endwalls form a pocket 27 which is open.

At the end of the `body opposite from the thick end wall 22 a rod 29 isattached. The rod is an integral portion ofthe body 17 and extendsoutwardly adjacent the bottom of the end wall 21. The rod as notedextends somewhat obliquely downwardly and inwardly. At some portion ofthe rod which in the chosen embodiment is the outer end portion there isprovided a knob 30 which is disc-like inl its proportions. The obliquerelationship of the rod is such that when the anchor lug is embedded inthe concrete of the core 10, all portions of the knob will be embeddedin the concrete beneath the outer surface 1S;

In order to anchor the lug in proper position when the core is beingcast and during hardening of the concrete there are provided lugs 31 and32. It is important to note that both of these lugs are on one of thewalls, namely, the wall 20. In each of the lugs is a threaded hole 33.Before the concrete of the core has been poured the anchor lug body 17is secured against the' inner surface 16 of the form 13 by bolts 34which pass through properly located holes 35 in the form.

Moreover', by having the lugs 31 and 32 on one side only of the body,the anchor lug may be located as near as is practically possible to afree end 36 of the core. Thus constructed the wire or cable 11 may bewound as near as possible to the end of thev core and hence provide amaximum of tensioning effect upon the exterior of the core. To assist ina proper locating of the endmost turn of the wire 11 an appropriatecoring element 37 capable of making a long oblique depression 37 may beemployed. The coring element 37 is normally long enough to extend intothe slot 25 to be certain of intercommunication between the depressionwhen formed and the interior of the pocket 27 after the mold has beenremoved.

After the form 13 has been removed subsequent to extraction of the bolts34, the core will be ready for application of. the wire 11. This iswound in a spiral path upon the exterior surface 15 of the core bysuitable machinery which maintains the Wire under high tension. At theinitiation of the Winding the wire may be anchored in an anchor lug ofthe type described. This may be accomplished by sliding a sleeve 40 ofspecial construction 4over the Wire 1.1. When the sleeve has thus beenplaced upon the wire leaving a short end 41 exposed the sleeve isgripped upon the wire. Sleeves of this kind are provided with afrangible porcelain lining which fractures when the sleeve is gripped atthe areas 42 and the frangible material forms a tight connection betweenthe sleeve and the Wire. Hence, when the sleeve holding the wire ispositioned Within the pocket 27, the Wire will be firmly anchored.

After the winding has progressed to the opposite end of the core, Whichmay be the end 36 by employment of appropriate winding and tensioningmachinery another sleeve 40 is applied over the wire at a location suchthat it will fall within the pocket 27 of the anchor lug at that end.While holding the wire under tension the slee-ve is gripped tightly uponthe wire forming a iirm grip as has been previously described. The wire4. may then be cut, leavinga comparable end 41 and while tension ismaintained by a grasp upon the wire somewhat remote from the end, thesleeve is slid into the pocket 27 and the wire passed into the slot 25.Once in position when tension is released the tensile hold upon the Wire11 will draw an endmost projection 43 of the sleeve against the insideface 28 of the end wall 22 and force the sleeve into the bottom of thepocket, aided as shown by the slope of the face 28.

The wire has been anchored securely as a result of the operationdescribed. Thereafter the coating 12 may be applied in some suitablefashion by virtue of which the entire exposed area of the wire 11 willbe covered and embedded in the coating. At the same time portions of thecoating will fill the pockets 27 and that portion of the depression 37not occupied by the wire.

It will be clear from the foregoing description that the anchor lugdevice is one of rugged characteristics, especially in that` the bodyand bar can be made integral with each other on a production basisbefore insertion into the mold by attachment to the inside surface asdescribed. Fashioned and mounted as is inherently possible in the deviceno welding operation is requisite. The device consequently comprises twoparts only, namely, the body and its attached bar in one instance, andthe sleeve 40 in the second instance. Once the sleeve has been attachedto the ends of the wire these two elements act as one and canibe quicklyand easily snapped into place by passing the wire through the slot 25.Because of the pull on the wire being arcuately inwardly toward the coreno means is necessary to anchor the wire in the core or close the endsof the slot 25. All parts of the joint lie flush with or depressedbeneath the outer surface 15 of the core 10. Should for any reason itbecome necessary to remove tension on the wire 11 the end of the Wirewithin the attached sleeve can be readily lifted from the pocket whensuilcient additional tension is applied to the adjacent portion of thewire. Any such removal must naturally take place before the plastercoating is applied.

The breadth of the slot 2S is not critical and can be wide enough totake wires of several diierent diameters as long as the portions of thesleeve which are of greatest diameter extend far enough outwardly toengage the inside face '28 of the end wall 22, immediately adjacent theslot.

By employing an anchoring'lugy device of the type herein described, it`becomes apparent that the entire body and its attached parts can beanchored in a position which will become flush with the exterior surfaceof the core once the mold has Ibeen removed. Being well embedded in thecore and by reason of having relatively thick walls at that portion ofthe body subject to greatest tension, the device can be built with aneconomic use of material. By employing the material in such form anadditional thickness is created Where the anchor lug device is attachedto the mold thereby to greatly convenience the molding operation.

Furthermore by reason of the simple arrangement described no specialattention need be given initially to thelength of the wire until it iscompletely wound. When this has been accomplished the wire can becut-off forming a free end and the sleeve 40 can then be slid intoproper position and clamped upon the wire. This is done while the wireis still held under tension by a grip upon the wire to the right of theanchor lug device as illustrated in Figures 1 and 2. Cnce the anchor lughas been fastened, the anchor lug with the wire is pressed into thepocket 22 and tension can thereafter be released upon the wire.

From the foregoing description it will be appreciated that the anchorlug device is of extremely simple form and construction and that itprovides ample strength and rigidity at the very necessary portionswhile minimizing the mass of material within those portions which willnot takegreat strain. lFurther by coupling theanchoring ability ofconcrete withthe anchoring ability of the body of the lng device, thestrength and ruggedness of the connection is improved and will not bedisturbed, especially after the coating 12 has been poured in place.

By reason of the structure and combination of the device being as hasbeen described, should there be a 'variation in the size of the wires orwire cable, no variation need be made in anchoring lug device other thana change in the inside diameter of the sleeve. Hence the anchoring ofthe wire is accomplished in a very simple, economical and expeditiousfashion and the device when used in the manner described will provide anample `anchoring effect for prestressed wire.

. While I have herein shown and `described my invention in what I haveconceived to be the most practical and preferred embodiment, it isrecognized that departures may be made therefrom within the scope of myinvention, which is not to be limited to the details disclosed hereinbut is to be accorded the full scope of the claims so as to embrace anyand all equivalent devices.

Having described my invention, what I claim as new and desire to secureby Letters Patent is:

l. A cable anchoring lug for embedding in a mass of concrete formed in amold comprising a bar adapted to engage in the concrete, a block on saidbar, means forming a pocket in said block, an end wall for said pocket,said end wall having a cable slot therethrough open at an exposed edge,and attachment means on said block adapted to temporarily receivecooperating attachment means on said mold, and an anchor sleeve orbreadth greater than the breadth of the slot receivable in said pocketwhen attached to a cable whereby the cable is anchored against said endwall.

2. A cable anchoring lug for embedding in a mass of concrete formed in amold comprising a bar having configurations thereon adapted to engage inthe concrete, a block integrally lfastened to said bar, means forming apocket in said block having end walls and side walls, one of said endwalls having a cable slot therethrough open at the exposed edge, andattachment means on `said block adapted to temporarily engage acooperating attachment means on said mold during pouring and setting ofthe concrete, and an anchor sleeve of size smaller than said pocket andof breadth greater than the breadth of the slot receivable in saidpocket when attached to a cable whereby the cable is anchored therein.

3. A cable anchoring lug for embedding in a mass of concrete formed in amold comprising a bar having con gurations thereon adapted to engage inthe concrete, a plate integrally secured to said bar intermediate theends, said plate having a relatively thick end wall, a relatively thinend wall at the opposite end, and side walls on said plate intermediatethe end Walls forming a pocket, said thick end wall having a cable slottherethrough communicating between the pocket and the exterior and openat an exposed edge, threaded holes in said block adapted to temporarilyreceive bolts extending through said mold, and an anchor sleeve of sizesmaller than the pocket and of diameter greater than the breadth of theslot receivable in said pocket when attached to a cable whereby thecable is anchored in the pocket.

4. A cable anchoring lug for embedding in a mass of concrete formed in amold comprising a bar having configurations thereon adapted to engage inthe concrete, a plate integrally secured to said bar, a relatively thickend wall and side walls on said plate forming a pocket, said thick endwall having a cable slot therethrough communicating between the pocketand the exterior and open at an exposed edge, threaded holes in the lugadjacent one of said side walls adapted to temporarily receive boltsextending through said mold, and an anchor sleeve of breadth greaterthan the breadth of the slot receivable in said pocket when attached toa cable whereby the cable is` anchored therein.

box adjacent opposite ends thereof adapted to tem-` porarily receivebolts extending through the mold, and an anchor sleeve of breadthgreater than the breadth of the slot and less than the breadth of thepocket receivable in the pocket when attached to a cable, whereby thecable is anchored therein.

6. A cable anchoring lug yfor embedding in a mass of concrete formed ina mold comprising an elongated box having walls forming an elongatedpocket, means forming an open slot in the wall at one end of the box,said last identified wall having an undercut inside face, a bar at theother end of the box extending endwise and obliquely relative to thebottom of the box, transversely extending protrusion means on the baradapted to engage the concrete whereby to anchor the box against endwisemovement, means forming threaded holes on one side of the box adjacentopposite ends thereof adapted to temporarily receive bolts extendingthrough the mold, and an anchor sleeve of breadth greater than thebreadth of the slot and less than the breadth of the pocket receivablein the pocket when attached to a cable, whereby the cable is anchoredtherein.

7. In a prestressed molded concrete pipe having a cable woundtherearound under tension, `an anchor connection assembly comprising asection initially embedded in the molded concrete pipe at apredetermined depth beneath the surface, said section including a block,end walls and side walls of said block forming an elongated pockethaving an open side substantially flush with said surface, a cable slotthrough one of said walls and extending inwardly from an exposed edge ofsaid last end wall, a sleeve having a size smaller than the pocket andhaving a cable aperture therethrough lined with a cable engaging coatingand subject to compression into anchoring engagement with the cable,said cable being in a position extending through said cable slot intothe pocket and within said sleeve, the portion of said cable in thesleeve and the sleeve having a position in the pocket with one end ofthe sleeve in abutting relationship with the inside face of said one endwall.

8. In -a prestressed molded concrete pipe having a cable woundtherearound under tension, an anchor connection assembly comprising abar having configuration means thereon initially embedded in the moldedconcrete pipe at a predetermined depth beneath the surface, a plateintegrally secured to said bar, a relatively thin end wall on the plate,a relatively thick end wall on the plate, and side walls on said plateintermediate said end walls, said walls forming an elongated pockethaving an open side coincident with the surface of the concrete, meansforming a cable slot through said thick wall communicating between thepocket and the exterior and extending inwardly frorn an exposed edge ofsaid thick wall, a sleeve shorter than the pocket having a cableaperture therethrough lined`I with a frangible coating and a series ofaxially spaced retention sections of the sleeve compressed intoengagement with the cable, said cable being in a position extendingthrough said cable slot into the pocket yand said sleeve, the portion ofthe cable retained in the sleeve having a position in the pocket withone end of the sleeve in abutting relationship with the inside face ofsaid thick end wall whereby the cable is anchored under tension to saidanchor connection.

9. A cable anchoring lug for embedding in a mass of concrete formed in amold comprising a block, means on said block adapted to engage in theconcrete whereby to anchorthe blockA against endwise movement, meansforming a pocket in said block, an end Wall for said pocket, SaidY endWall having -a cable slot therethrough open at an exposed edge, andattachment means on said block adapted to temporarilyv receivecooperating attachment means on said mold, and an anchor sleeve ofbreadth greater than the breadth of the slot receivable in said pocketwhen attached to a cable whereby the cable is anchored against said endwall.

References Cited in the le of this patentV UNITED STATES PATENTS ErbeApr. 8, 1952

